Maintenance of platelet inhibition during antiplatelet therapy

ABSTRACT

A method for reducing or maintaining platelet inhibition in a patient by administering cangrelor prior to an invasive procedure is described. The method of this invention can be used for patients in need of antiplatelet therapy or at risk of thrombosis. The method can further be used in patients who were previously treated with long-acting platelet inhibitors without increasing the risk of excessive bleeding.

This invention is a continuation of U.S. application Ser. No. 16/356,798(now U.S. Pat. No. 10,744,149) filed on Mar. 18, 2019, which is acontinuation of Ser. No. 14/195,798 (now U.S. Pat. No. 10,231,987) filedon Mar. 3, 2014, which is a continuation of Ser. No. 13/209,271 filed onAug. 12, 2011, now abandoned, which is a continuation-in-part of U.S.application Ser. No. 12/990,332 (now U.S. Pat. No. 8,871,736) filed onAug. 15, 211, which claims priority to PCT/US09/043820 filed on May 13,2009, which claims priority to U.S. provisional application No.61/127,424 filed on May 13, 2008. Each of the above referencedapplications is incorporated herein by reference.

FIELD OF THE INVENTION

The instant invention relates to the field of platelet inhibition, andin particular to methods of maintaining or reducing platelet activity inpatients undergoing an invasive procedure.

BACKGROUND OF THE INVENTION

Anti-platelet therapy has been shown to reduce clinical ischemic eventsand improve outcomes for acute coronary syndrome (ACS) patients.Currently, the approved anti-platelet products include aspirin andthienopyridines, such as clopidogrel and ticlopidine. One of the mostwidely prescribed thienopyridines is clopidogrel, which is also known asPlavix®.

Thienopyridines such as clopidogrel irreversibly inhibits P2Y₁₂receptors which play an active role in platelet activation. In thenormal state, when blood vessels are damaged, platelet activationmediated by P2Y₁₂ receptors play an important role to arrest bleeding atthe site of injury. In a diseased state, platelet activation leads tovascular occlusion and ischemic damage. Thus, P2Y₁₂ receptorsantagonists play a key role in antiplatelet therapy in assisting toprevent coronary artery disease and for the immediate treatment of ACSand percutaneous coronary intervention (PCI).

Physicians often prescribe dual anti-platelet therapy, which includeaspirin and a thienopyridine, such as clopidogrel for patients who havebeen diagnosed with ACS or for patients who are showing symptomsassociated with ACS as a first line treatment. Pending furtherexaminations, these patients may continue with this treatment or receiveother treatments such as coronary artery bypass grafting (CABG) and PCI.Consistent with this practice, current American College ofCardiology/American Heart Association (ACC/AHA) guidelines recommendimmediate initiation of dual anti-platelet therapy of clopidogrel andaspirin after a patient is diagnosed with ACS. Similarly, patients thathave received a bare metal stent or drug-eluting stent are also put onthe dual clopidogrel and aspirin therapy for an extended period of timeto prevent an ischemic event. For instance, a post hoc analysis of ablinded, placebo-controlled trial suggest a benefit of platelet activityinhibition in terms of decreased thrombotic events prior to CABG (Fox KA et. al, Circulation. 2004; 110; 1201-08). For many patients, this dualanti-platelet therapy provides tremendous clinical benefits, andminimizes the risks of ischemic events, such as heart attack and stroke.

Dual anti-platelet therapy, however, has drawbacks. Cessation ofclopidogrel may increase the incidence of ischemic events in theshort-term due to a “rebound” effect of platelet activation (Brilakis ES et al, J Am CO Cardiol. 2007 Jun. 5; 49(22):2145-50; Ho P M et al,JAMA. 2008 Feb. 6; 299(5):532-9).

In addition patients receiving dual anti-platelet therapy experience anincreased incidence of blood transfusions and bleeding complicationswhile undergoing surgery and other invasive procedures. This isparticularly true for ACS patients who often receive surgery, such asCABG and PCI, and other invasive procedures, such as implantation of abare metal stent (BMS) or drug-eluting stent (DES). Because aspirin andthienopyridines are irreversible, long-acting platelet antagonistsreversal of the inhibition of platelet function occurs only as newplatelets are generated and therefore even after discontinuation, theireffect can lasts several days before being completely eliminated.

Thus, for patients under dual therapy who also require surgery such asCABG sustained platelet inhibition poses an unacceptable risk ofbleeding. Consequently, it has been recommended by the ACC/AHA and theSociety of Thoracic Surgeons (STS) guidelines to cease thienopyridinetherapy prior to undergoing non-emergent cardiac surgical procedures tominimize bleeding risks. Thus, patients are often required to stop dualanti-platelet therapy and wait for five to seven days before anyinvasive procedures can be performed.

On the other hand, even though clopidogrel treatment prior to CABG doesincrease bleeding due to its irreversibility, platelet P2Y12 inhibitiondoes appear to prevent ischemic events in patients requiring CABG. As aresult, physicians often face the difficult choice of discontinuingclopidogrel and aspirin prior to surgery and risking a potentialischemic event in the unprotected perioperative period or delayingsurgery until the time at which clopidogrel is no longer required.

Currently, no ultra short-acting platelet inhibitors are available thatallow maintenance of platelet inhibition before an invasive procedurewithout increasing bleeding complications at the time of an invasiveprocedure. Potentially, effective platelet inhibition with an ultrashort-acting platelet inhibitor during the period of clopidogrelwithdrawal may protect patients from ischemic events and also preservenormal hemostasis at the time of surgery.

Therefore, a need exists for a new therapy for patients who areundergoing surgery (this includes therapy prior to, during, and post) orother invasive procedures, and who have a need for anti-platelettherapy. This new therapy maintains platelet inhibition at acceptablelevels while allowing for rapid restoration of platelet function afterdiscontinuation so that patients may undergo surgical procedures withoutincreasing the risk of bleeding complications.

In addition, a need exists for a new therapy for patients who, forwhatever reason, cannot be administered thienopyridines, such asclopidogrel or Plavix®, or cannot receive orally administeredantiplatelet therapies.

SUMMARY OF THE INVENTION

As shown herein, the present invention describes compositions andmethods of maintaining or reducing platelet activity in a patient priorto the patient undergoing an invasive procedure by administering aneffective amount of short-acting P2Y₁₂ inhibitor.

In one aspect of this invention methods are described for administeringan effective amount of a short-acting P2Y₁₂ inhibitor to maintain orreduce platelet activity in a patient before an invasive procedure, in apatient previously treated with long-acting irreversible plateletinhibitors without an increase risk in bleeding.

In a related embodiment of this method, other therapeutic agents areadministered concurrently with the reversible, short-acting P2Y₁₂inhibitor.

In another related embodiment of this method, the risk of bleeding isnot increased.

In another aspect of this invention, a short-acting P2Y₁₂ inhibitor isuse to maintain or reduce platelet activity in patients perioperativelywhere oral antiplatelet therapy is contraindicated. The reversible,short-acting P2Y₁₂ inhibitor can be administered to a patient as a bolusand or a continuous intravenous infusion.

In another aspect of this invention, methods are described where aneffective amount of a short-acting P2Y₁₂ inhibitor is administered tosufficiently reduce or maintain at least 60% platelet inhibition orP2Y₁₂ reaction unit (PRU) values less than 240 prior to the patientundergoing an invasive procedure

In a related embodiment to this method, the short-acting P2Y₁₂ inhibitoris discontinued thereby allowing platelet activity to return topre-administration levels as measured by PRU being greater than 240.

In yet another aspect of the present invention, methods are describedfor administering a reversible, short-acting P2Y₁₂ inhibitor to apatient who was previously administered a thienopyridine, and ceasingadministration of the short-acting P2Y₁₂ inhibitor wherein the PRUlevels is similar to pre-administration levels of the short-acting P2Y₁₂inhibitor, prior to said patient undergoing an invasive procedure.

In another aspect of this invention, a method of treating or preventingthrombosis is described by administering a short-acting P2Y₁₂ inhibitorto a patient previously treated with a long-acting irreversible plateletinhibitor, where the risk of bleeding is not increased.

In another aspect of this invention, an intravenous pharmaceuticalcomposition of cangrelor is described for maintaining or reducingplatelet inhibition.

In another aspect of this invention, a method for preparing anintravenous cangrelor composition for inhibiting platelet activity bycombining cangrelor with mannitol, sorbitol and intravenouslyadministrable excipient for maintaining PRU values at a certain level.

BRIEF DESCRIPTION OF THE FIGURES

Understanding of the present invention will be facilitated byconsideration of the following detailed description of the embodimentsof the present invention taken in conjunction with the accompanyingdrawings, in which like numerals refer to like parts and in which:

FIG. 1 is a graphical presentation of the percent inhibition ofADP-induced platelet aggregation and effect on bleeding time.

FIG. 2 is a flow chart of the time periods through which the presentinvention is performed.

FIG. 3 is a flow chart of a study demonstrating an exemplary method.

FIG. 4A is a table of the studied assessments by time point. FIG. 4Bshows the footnotes of the table in FIG. 4A.

DETAILED DESCRIPTION

It is to be understood that the figures and descriptions of the presentinvention have been simplified to illustrate elements that are relevantfor a clear understanding of the present invention, while eliminating,for the purpose of clarity, many other elements found in typicalantiplatelet therapies. Those of ordinary skill in the art willrecognize that other elements and/or steps are desirable and/or requiredin implementing the present invention. However, because such elementsand steps are well known in the art, and because they do not facilitatea better understanding of the present invention, a discussion of suchelements and steps is not provided herein. The disclosure herein isdirected to all such variations and modifications to such elements andmethods known to those skilled in the art. Furthermore, the embodimentsidentified and illustrated herein are for exemplary purposes only, andare not meant to be exclusive or limited in their description of thepresent invention.

The present invention provides a method for inhibiting plateletactivities in patients prior to undergoing an invasive procedure.

The methods described in the present invention maintains plateletinhibition at acceptable and targeted levels, while allowing for rapidrestoration of platelet function after discontinuation of the drugtherapy so that patients may undergo invasive procedures withoutincreasing the risk of bleeding complications.

The described methods can be used for patients in need of treatment toreduce or maintain platelet inhibition. Preferably the described methodscan be used in patients at risk of thrombotic events. More preferablythe embodiments of the present invention are directed to patientsdiagnosed with symptoms of stable or unstable angina, vascular ischemicevents, atherosclerosis, acute coronary syndrome, as well as STEMI orN-STEMI. The described methods can also be used for patients havingpreviously received a stent, such as a bare metal stent or adrug-eluting stent, for the treatment or prevention of stent thrombosis.While the present invention is generally targeted for use with humanpatients, the described methods can be used on any living animal.

The present invention further provides a method for reducing ormaintaining adequate P2Y₁₂ inhibition with rapid reversibility upondiscontinuation of long-acting irreversible platelet inhibitors prior topatients undergoing invasive procedures without increasing the risk ofbleeding complications.

Definitions

Long-acting P2Y₁₂ inhibitors refer to compounds which inhibit P2Y₁₂receptor activities, having a slow on-set and long eliminationhalf-life. Examples of long-acting P2Y₁₂ inhibitors are typicallyformulated as oral dosage forms. One example of long-acting P2Y₁₂inhibitor is long-acting irreversible P2Y₁₂ inhibitors. Examples oflong-acting irreversible P2Y₁₂ inhibitors include thienopyridines.Examples of thienopyridines, include without limitation clopidogrel,ticloridine, and prasugrel and such other compounds having similarproperties. Clopdogrel is a pro-drug that requires metabolism forconversion to the active metabolite.

Short-acting reversible, P2Y₁₂ inhibitors refer to compounds whichinhibits P2Y₁₂ receptor activities, having a fast onset time and arelatively short metabolism rate as compared to those ofthienopyridines. Examples of a short-acting, reversible P2Y₁₂ inhibitorinclude, without limitations, cangrelor, ticagrelor and PRT060128. Itshould be noted that the present invention is not limited to theseexamples. Additional compounds that have similar properties may also beused in the present invention.

One particularly preferred example of a reversible, short-acting P2Y₁₂inhibitor is cangrelor. Cangrelor is a potent, direct, and reversibleantagonist of the platelet P2Y₁₂ receptor. Cangrelor has a half life ofapproximately less than 10 minutes, allowing for a return to normalplatelet function in a very short period of time upon discontinuation ofthe drug. By reducing the need for a compound to be metabolized foractivity, and by having a relatively short half life, reversible,short-acting P2Y₁₂ inhibitors are considered “reversible”, meaning thatfull platelet functionality may return rather quickly as compared tothienopyridines.

The binding of cangrelor to the P2Y₁₂ receptor inhibits plateletactivation as well as aggregation when mediated in whole or in part viathis receptor. Cangrelor can be derived completely from syntheticmaterials, and is an analogue of adenosine triphosphate (ATP), thenatural antagonist found in humans specific to the P2Y₁₂ receptor sites.

The chemical structure for cangrelor is depicted below as Formula I.

Cangrelor is clinically well tolerated and safe and does not react withaspirin, heparin or nitroglycerin. Unlike orally dosed thienopyridines,cangrelor can be administered intravenously and binds directly to P2Y₁₂receptor sites of platelets. In each of the embodiments of the presentinvention, the term “cangrelor” encompasses the compound of Formula I aswell as tautomeric, enantiomeric and diastereomeric forms thereof, andracemix mixtures thereof, other chemically active forms thereof, andpharmaceutically acceptable salts of these compounds, including atetrasodium salt. These alternative forms and salts, processes for theirproduction, and pharmaceutical compositions comprising them, are wellknown in the art and set forth, for example, in U.S. Pat. No. 5,721,219.Additional disclosure relevant to the production and use of cangrelormay be found in U.S. Pat. Nos. 5,955,447, 6,130,208 and 6,114,313, aswell as in U.S. Appin. Publication Nos. 2006/0270607 and 2011/0112030.

Invasive procedures means any technique where entry to a body cavity isrequired or where the normal function of the body is in some wayinterrupted by a medical procedure and/or treatment that invades(enters) the body, usually by cutting or puncturing the skin and/or byinserting instruments into the body. Invasive procedures can includecoronary artery bypass grafting (CABG), orthopedic surgeries, urologicalsurgeries, percutaneous coronary intervention (PCI), other generalinvasive procedures, such as endarterectomy, renal dialysis,cardio-pulmonary bypass, endoscopic procedures or any medical, surgical,or dental procedure that could result in excessive bleeding orhemorrhage to the patient.

Perioperative means the period of a patient's invasive procedure whichcan occur in hospitals, surgical centers or health care providers'offices. Perioperative includes admission, anesthesia, surgery, torecovery.

Thrombosis is the formation of a blood clot (thrombus) inside a bloodvessel obstructing the flow of blood through the circulatory system.When a blood vessel is injured, the body uses platelets and fibrin toform a blood clot to prevent blood loss. Some examples of the types ofthrombosis include venous thrombosis which includes deep veinthrombosis, portal vein thrombosis, renal vein thrombosis, jugular veinthrombosis, Budd-Chiari syndrome, Paget-Schroetter disease, cerebralvenous sinus thrombosis, cerebral venous sinus thrombosis and arterialthrombosis which includes, stroke and myocardial infarction.

Dosage and Administration

As used herein, the terms “dose”, “dosage”, “unit dose”, “unit dosage”,“effective dose”, “effective amount” and related terms refer tophysically discrete units that contain a predetermined quantity ofcangrelor, calculated to produce a desired therapeutic effect. Theseterms are synonymous with the therapeutically effective amounts andamounts sufficient to achieve the stated goals of the methods disclosedherein.

When administered as an intravenous (IV) formulation, a pharmaceuticalcomposition comprising cangrelor may be administered as a bolus, as acontinuous infusion, or as a bolus followed by a continuous infusion.When administered as a bolus, a dose of about 5, 10, 15, 20, 25, 30, 35,40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 μg/kg cangrelor,or more, is administered to the patient. In preferred embodiments,between about 20 μg/kg and about 40 μg/kg cangrelor is administered,more preferably about 30 μg/kg. When administered as a continuousinfusion, cangrelor may be administered at about 0.1, 0.5, 0.75, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30 μg/kg/min, or more to thepatient. In preferred embodiments, between about 0.1 and about 5μg/kg/min cangrelor is administered, more preferred is administration ofcangrelor in the range of about 0.5 μg/kg/min to about 2 μg/kg/min. Evenmore preferred is a dosage range of cangrelor at about 0.5 μg/kg/min toabout 1 μg/kg/min. The skilled artisan will understand that differentbolus and intravenous dosages from those set forth here may beadministered based on the particular characteristic of the patient.Thus, the dosage amount can be varied from the dosage amount presentlydescribed, however, the dosage given must be sufficient to reduce ormaintain the PRU values below about 240 as measured by VerifyNow®.

In addition, the skilled artisan will understand that the exact amountof reversible short-acting P2Y₁₂ inhibitor to be administered to apatient will vary depending on the degree of platelet activityinhibition that is sought. For example, the amount of reversibleshort-acting P2Y₁₂ inhibitor to be administered to a patient during aninvasive procedure that will result in bleeding may be much less thanthe amount that would be administered when such a procedure is not beingperformed.

The dosage of the reversible short-acting P2Y₁₂ inhibitor may beadministered as a continuous intravenous infusion or it may beadministered in discrete does, such as between 1 and 48 doses, or more,per 24 hour period. The dosage of the reversible short-acting P2Y₁₂inhibitor may vary over time, with a lower dosage being initiallyadministered, followed by an increased dosage for a sustained period oftime, with an optional decrease in the dosage prior to completecessation of administration of the reversible short-acting P2Y₁₂inhibitor. Such a dosing regime may be used in conjunction with theconcurrent cessation of thienopyridine and/or aspirin treatment andbeginning of reversible short-acting P2Y₁₂ inhibitor. Such dosing regimecan also ensure a constant level of platelet activity inhibition.

In other forms, a reversible, short-acting P2Y₁₂ inhibitor can beadministered at a daily dose of from 0.1 mg to 1000 mg, which may be individed doses e.g. up to 6 times per day.

The total amount of reversible, short-acting P2Y₁₂ inhibitor that may beadministered to a subject may be between about 0.01 and 1000 mg per 24hour period, with exemplary totals of about 0.5, 0.75, 1.0, 1.25, 1.5,1.75, 2.0 and 2.5 mg per 24 hour period.

In each of the embodiments where the pharmaceutical composition isadministered as continuous intravenous infusion, the infusion maycontinue for at least about 2 days to about 7 days. The skilled artisanwill understand that the period of time over which the pharmaceuticalcomposition is administered may be shorter or longer than the indicatedtimes due to the particular characteristics of a patient. Administrationof a reversible, short-acting P2Y₁₂ inhibitor can be made several daysto several hours prior to the invasive procedure. One example is toadminister a reversible, short-acting P2Y₁₂ inhibitor about 7 days toabout 1 hour prior to an invasive procedure. To maintain plateletinhibition, the reversible short-acting P2Y₁₂ inhibitor should beadministered within about 2 days to about 7 days of ceasingadministration of the long-acting platelet inhibitor. A further exampleis to administer the reversible short-acting P2Y₁₂ inhibitor withinabout 3 days of ceasing administration of the long-acting plateletinhibitor. Discontinuation of the reversible short-acting P2Y₁₂inhibitor can be performed about 1 to 6 hours before a surgicalprocedure. It should be noted that the duration for administering areversible, short-acting P2Y₁₂ inhibitor often vary depending on whichreversible, short-acting P2Y₁₂ inhibitor is used and the particularcharacteristic of the patient. One skilled in the art can vary theduration of administration so long as platelet inhibition as measured byVerifyNow® is below about 240.

Reversible, short-acting P2Y₁₂ inhibitors, such as cangrelor, ticagreloror PRT060128, can be administered using any of the various methods anddelivery systems known to those skilled in the art. The administeringcan be performed, for example, intravenously, orally, via implant,transmucosally, transdermally, intramuscularly, intrathecally, andsubcutaneously. According to one preferred embodiment, a reversible,short-acting P2Y₁₂ inhibitor may be administered intravenously. It iscontemplated that the reversible, short-acting P2Y₁₂ inhibitor can beadministered intravenously in accordance with the present inventionduring surgery, when the patient is comatose, or any other such scenariowhere the oral administration of the inhibitor is prohibited.

In the case of administering the therapy prior to surgery in accordancewith one embodiment of the present invention, such use allows patientsto undergo surgery or other invasive procedures without excessiveperioperative bleeding. For example, as described herein, cangrelorinfusion can maintain platelet inhibition levels of approximatelygreater than or equal to about 60% after discontinuation of clopidogrelwithout an increase in bleeding risk and before the invasive procedurebegins.

In addition to the pharmaceutical compositions of the present inventioncomprising cangrelor, the skilled artisan will understand thatadditional therapeutic agents may be used in combination with cangrelor.By way of non-limiting examples, compounds such as aspirin, bibalirudinunfractionated heparin, low molecular weight heparin, fondaprinuxsodium, warfarin, coumarins, thromoblytics such as streptokinase,Alteplase, Reteplase, urokinse, Tenecteplase, glycoprotein Ilb/Illainhibitors such as eptifibatide, abciximab, tirofiban, epsilonamino-caproic acid, and tranexamic acid, can be used as concomitantmedications.

Measurement of Platelet Activity

Assessment of platelet function can be determined by use of theVerifyNow® assay of which the System User Manual (Accumetrics, SanDiego, Calif., 2009) is incorporated by reference in its entirety. TheVerifyNow® P2Y₁₂ assay is a point of care device for the assessment ofthe level of inhibition of platelet activation specifically designed forpatients exposed to thienopyridines. It should be understood that anyassay system for determining levels of inhibition of platelet activationcan be used, as understood by those having skill in the art. Bloodsamples for the VerifyNow® P2Y₁₂ assay can be collected into GreinerBio-One Vacuette partial fill blood collection tubes (2 mL fill volume)containing 3.2% citrate, or by other suitable means.

The VerifyNow® P2Y12 assay is a rapid platelet-function cartridge-basedassay that activates platelets using adenosine diphosphate (ADP), butalso uses prostaglandin E1 to suppress the ADP-induced P2Y1-mediatedincrease in intracellular calcium levels to increase the specificity ofthe test for inhibition of the P2Y₁₂ receptor. The test cartridgecontains a lyophilized preparation of human fibrinogen coated beads,platelet agonist, buffer and preservative. Fibrinogen-coatedmicroparticles are used to bind to available platelet receptors. Whenthe activated platelets are exposed to the fibrinogen-coatedmicroparticles, agglutination occurs in proportion to the number ofavailable platelet receptors. The whole-blood citrate mixture is addedto the cartridge, and agglutination between platelets and coated beadsis recorded. The VerifyNow® P2Y₁₂ device is a turbidimetric opticaldetection system, which measures platelet induced aggregation as anincrease in light transmittance. VerifyNow® P2Y₁₂ testing can be used atany time point as described herein to assess the level of inhibition ofplatelet activity.

Assay results are expressed in P2Y₁₂ reaction units (PRU) (VerifyNow®System User Manual (Accumetrics, San Diego, Calif., 2009)). Highplatelet reactivity, as assessed by VerifyNow® P2Y₁₂ assay was definedas a PRU value greater than 240. The lower the PRU value the greater theinhibition of the P2Y₁₂ receptor resulting in reduction of the plateletactivity. For the methods described in this invention, the PRU level ispreferably maintained during the period of cangrelor administration at240 or less. In a preferred embodiment of the present invention, thedose of cangrelor was 0.75 μg/kg/min. This dose was maintained for about2 to about 7 days. PRU values in the patients were less than or equal to240.

It would be understood by those skilled in the art that increasing theconcentration of cangrelor infusion will result in a decrease in PRUvalues and an increase in the percent platelet inhibition. It istherefore preferred to measure PRU values during the course of cangrelorinfusion and to adjust the infusion rate accordingly.

Pharmaceutical Compositions

In each aspect and embodiment of the present invention, short-actingreversible platelet inhibitor is administered to a patient in the formof a pharmaceutical composition comprising the active ingredient and,optionally, a pharmaceutically acceptable carrier, diluent and/orexcipient. Thus, the present invention encompasses: (i) a pharmaceuticalcomposition comprising cangrelor, and a pharmaceutically acceptablecarrier, diluent and/or excipient;

Suitable carriers and diluents are well known to those skilled in theart and include saline, such as 0.9% NaCl, buffered saline, dextrose(e.g., 5% dextrose in water), water, Water-for-Injection (WFI),glycerol, ethanol, ringer's solution, propylene glycol, polysorbate 80(Tween-80), 0.002% polysorbate 80 (Tween-80), poly(ethylene)glycol 300and 400 (PEG 300 and 400), PEGylated castor oil (e.g. Cremophor EL),poloxamer 407 and 188, a cyclodextrin or a cyclodextrin derivative(including HPCD ((2-hydroxypropyl)-cyclodextrin) and(2-hydroxyethyl)-cyclodextrin, hydrophilic and hydrophobic carriers, andcombinations thereof. Hydrophobic carriers include, for example, fatemulsions, lipids, PEGylated phospholipids, polymer matrices,biocompatible polymers, lipospheres, vesicles, particles, and liposomes.Excipients included in a pharmaceutical composition have differentpurposes depending, for example on the nature of the drugs, and the modeof administration. Examples of generally used excipients include,without limitation: stabilizing agents, solubilizing agents andsurfactants, buffers, antioxidants and preservatives, tonicity agents,bulking agents, lubricating agents, emulsifiers, suspending or viscosityagents, inert diluents, fillers, disintegrating agents, binding agents,wetting agents, lubricating agents, antibacterials, chelating agents,sweeteners, perfuming agents, flavouring agents, coloring agents,administration aids, and combinations thereof.

The pharmaceutical composition may contain common carriers andexcipients, such as cornstarch or gelatin, lactose, sucrose,microcrystalline cellulose, kaolin, mannitol, sorbiton, dicalciumphosphate, sodium chloride, alginic acid, croscarmellose sodium, andsodium starch glycolate.

The pharmaceutical compositions of the present invention may beformulated, for example, for oral, sublingual, intranasal, intraocular,rectal, transdermal, mucosal, topical or parenteral administration.Parenteral modes of administration include without limitation,intradermal, subcutaneous (s.c., s.q., sub-Q, Hypo), intramuscular(i.m.), intravenous (i.v.), intraperitoneal (i.p.), intra-arterial,intramedulary, intracardiac, intra-articular (joint), intrasynovial(joint fluid area), intracranial, intraspinal, and intrathecal (spinalfluids). Any known device useful for parenteral injection or infusion ofdrug formulations can be used to effect such administration. In notedaspects and embodiments of the present invention, administration of thepharmaceutical compositions is via parenteral administration, preferablyintravenous administration.

In intravenous (IV) administration, a sterile formulation of thepharmaceutical compositions of the present invention and optionally oneor more additives, including solubilizers or surfactants, can bedissolved or suspended in any of the commonly used intravenous fluidsand administered by infusion. Intravenous fluids include, withoutlimitation, isotonic infusion media such as physiological saline, 0.9%NaCl, phosphate buffered saline, 5% dextrose in water, 0.002%polysorbate 80 (Tween-80) in water or Ringer's solution.

Pharmaceutical compositions comprising cangrelor of the presentinvention include pharmaceutical compositions comprising from about 0.1to about 50 mg/ml of cangrelor. Particular examples of pharmaceuticalcompositions comprising cangrelor include the following: (i) cangrelorat a concentration of about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10mg/mL in 0.9% NaCl, and (ii) cangrelor at a concentration of about 0.1,0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mg/mL in 5% dextrose in water. Thepharmaceutical composition may further comprise a pharmaceuticallyacceptable carrier or diluent such as sorbitol and mannitol.

One method for preparing a cangrelor composition includes dissolving 50mg lyophilized cangrelor or its pharmaceutically acceptable salt byinjecting 5 ml sterile water into a 10 ml vial containing cangrelor orits pharmaceutically acceptable salt thereof, preparing an intravenousbag by immediately adding the dissolved cangrelor to an intravenous bagcontaining saline solution in volumes such as 250 ml, 500 ml, or 1000 mlof saline solution and mixing the intravenous bag thoroughly foradministration. Cangrelor compositions should be prepared immediatelyprior to administration via infusion. It is within the skilled in theart to vary the volume of saline and amount of cangrelor in theexemplary method described above to achieve the dosage amount describedin the preferred embodiments.

The described methods can be used for patients diagnosed with symptomssuch as stable or unstable angina, vascular ischemic events,atherosclerosis, acute coronary syndrome, including STEMI or N-STEMI.The described methods can also be used for patients having previouslyreceived a stent, such as a bare metal stent or a drug-eluting stent,and the treatment or prevention of stent thrombosis.

The described methods can be used for a patient before, during, andafter an invasive procedure, such as coronary artery bypass grafting,orthopedic surgeries, urological surgeries, percutaneous coronaryintervention, other general invasive procedures, such as endarterectomy,renal dialysis, cardio-pulmonary bypass, endoscopic procedures or anymedical, surgical, or dental procedure that could potentially lead toexcessive bleeding or hemorrhage.

Further, the described methods of the present invention can be used in apatient who cannot be orally administered therapies and, for whateverreason, cannot be administered long lasting thienopyridines, such asclopidogrel or Plavix®.

Results of the Methods

To determine how to administer a reversible, short-acting P2Y₁₂inhibitor or the amount of a reversible, short-acting P2Y₁₂ inhibitor tobe administered, the pharmacokinetic profile of the reversible,short-acting P2Y₁₂ inhibitor can be analyzed using the methodswell-known to a person skilled in the art.

For example, the pharmacokinetics of cangrelor has been shown to besubstantially linear, and its steady-state plasma concentrations can beachieved in less than approximately 5 minutes following theadministration of an intravenous infusion.

Cangrelor produced potent inhibition of ADP-induced platelet aggregationex vivo with 1050 7.72+/−1.95 ng/m L. As may be seen in FIG. 1, over 80%inhibition was achieved at doses of about 0.5 μg/kg/min and above.Inhibition by cangrelor was rapidly reversible and platelet aggregatoryresponse restored close to baseline within one hour of stopping theinfusion. An infusion dose of approximately about 0.75 μg/kg/min ofcangrelor can also maintain adequate antiplatelet activity duringinfusion in the targeted patient prior to an invasive procedure.

It has been determined that consistent and complete platelet inhibitioncan be maintained throughout cangrelor infusion with full recovery ofplatelet function within approximately one hour of infusion cessation.Clopidogrel administration at the termination of cangrelor infusion maylead to the expected degree of platelet inhibition, which may bemeasured by P-selectin expression, electrical impedance and lighttransmittance aggregometry.

Example 1

Without limitations, FIG. 2 provides a brief summary as to how themethods described in the present invention may be used in a patient inneed thereof. It should be understood that the method of the presentinvention is not limited to the procedure described in FIG. 2.

FIG. 2, shows a screening period 210 used for determining the dosagenecessary for achieving platelet inhibition greater than apre-determined level, for example, of approximately 60%. A pre-operativeperiod 220 of up to approximately 7 days prior to surgery can be usedfor administration of a reversible, short-acting P2Y₁₂ inhibitor. Anintra-operative period 230 lasting from the discontinuation of thereversible, short-acting P2Y₁₂ inhibitor to the end of surgery can beused.

During the screening period 210, the dosage of a reversible,short-acting P2Y₁₂ inhibitor, necessary to achieve platelet inhibitiongreater than approximately 60% can be determined. Other suitable levelsof percent inhibition are approximately 65, 70, 75, 80, 85, 90, 95 and100%. For example, intravenous infusion of a reversible, short-actingP2Y₁₂ inhibitor can be administered to a patient in doses typicallyranging from about 0.5 p/kg/min to about 5.0 p/kg/min, preferably about0.5 p/kg/m in to about 2.0 p/kg/m in and particularly at doses of 0.5μ/kg/min, 0.75 μ/kg/min, 1.0 μ/kg/min, 1.5 μ/kg/min and 2.0 μ/kg/m in,until measured platelet inhibition is greater than the pre-determinedlevel. Smaller or larger doses may also be used as needed to achieve therequired level of platelet inhibition.

Optionally, the dosage of a reversible, short-acting P2Y₁₂ inhibitor forany particular patient can also be determined ahead of time, so as toreduce the need to give multiple doses to achieve the required level ofplatelet inhibition. In all instances where measurement of plateletinhibition is needed, a baseline value should be obtained to accuratelydetermine when acceptable levels have been reached.

During pre-operative period 220, administration of a reversible,short-acting P2Y₁₂ inhibitor can be initiated the day the decision ismade to discontinue the long-acting irreversible platelet inhibitor andmay be continued throughout pre-operative period 220. In anotherembodiment, administration of cangrelor can be made within 3 days ofceasing administration of the long-acting irreversible plateletinhibitor.

A patient can undergo CABG within 3 days of ceasing administration ofthe long-acting irreversible platelet inhibitor. The dose of such areversible, short-acting P2Y₁₂ inhibitor can remain constant or can beperiodic during the treatment period. Preferably the dosage of cangrelorremain continuous during the treatment period of about 2 to about 7days. Treatment with reversible, short-acting P2Y₁₂ inhibitor may thenbe terminated from about one hour to about 6 hours before an invasiveprocedure.

Also during pre-operative period 220, any number of procedures and/ortests can be performed in conjunction with the present invention, suchas hemoglobin, hematocrit, white blood cells, and platelet counttesting; serum creatinine testing; measurement of inhibition of plateletactivation; and assessment of concomitant medications, adverse events,serious adverse events and other various clinical endpoints.Additionally, procedures such as CK and CK-MB and VerifyNow® P2Y₁₂assays, for example, can be performed within 24 hours prior to surgery.

During intra-operative period 230, administration of a reversible,short-acting P2Y₁₂ inhibitor can be stopped between from about at least1 hour and up to approximately 3 hours prior to administration ofanesthesia for surgery. Basic standard of care treatment is used for thesurgical period as understood by those having skill in the art.Collection of concomitant medications and assessments of adverse events,serious adverse events and clinical endpoints can also be performedduring this period as needed.

Example 2

FIG. 3 describes is a non-limiting exemplary method for maintaining orreducing platelet activity in patients who were previously treated withthienopyridine prior to undergoing an invasive procedure such as CABG.

In FIG. 3, a total of 207 patients were studied. Patients were includedin from this study if they met all of the following criteria: 1. Must beat least 18 years of age; 2. Anticipate non-emergent coronary arterybypass graft (CABG) surgery, either “onpump” or “off-pump,” no soonerthan 48 hours from randomization but no longer than 7 days fromrandomization, with patient to remain hospitalized until planned CABG;3. Have received a thienopyridine (at least 75 mg of clopidogrel, 500 mgticlopidine, or 10 mg prasugrel) within 72 hours prior to enrollment inthe study for either: the treatment of an acute coronary syndrome,regardless of time from ACS, and/or as long-term preventative therapyfollowing drug-eluting or bare metal stent treatment.

Patients were excluded from the study if any of the following exclusioncriteria applied prior to randomization:

1. Confirmed or suspected pregnancy (if woman of child-bearingpotential) or lactating females; 2. Cerebrovascular accident within oneyear; 3. Intracranial neoplasm or history of intracranial surgery; 4.History of bleeding diathesis; 5. Thrombocytopenia (platelet count ofless than 100,000/pL); 6. Known International Normalized Ratio (INR)greater than 1.5 at screening; 7. Requirement for dialysis treatment(hemodialysis or peritoneal); 8. Estimated Glomeular filtration rateeGFR <30 ml/min; 9. Administration of abciximab within 24 hours ofrandomization or administration of eptifibitide or tirofiban within 12hours of randomization; 10. Plans to continue oral anticoagulant,thienopyridine or GPIIb/IIIa antagonist therapy in the pre-operativeperiod; 11. Known or suspected coagulopathy; 12. Refusal to receiveblood transfusion; 13. Receipt of fibrinolytic therapy in the 12 hourspreceding randomization; 14. Allergy, hypersensitivity, orcontraindication to cangrelor, mannitol, sorbitol, or microcrystallinecellulose; 15. High likelihood of being unavailable for follow-up; 16.Participation in other studies involving the evaluation of otherinvestigational drugs or devices within 30 days of randomization, 17.Any disease or condition which, in the judgment of the health careprovider, would place the patient at undue risk by participating in thestudy.

Patients were randomized into two groups, a cangrelor plus standard ofcare (SOC) group, and a placebo plus SOC group. A dose study wasperformed, for cangrelor plus SOC and placebo plus SOC respectively. Adose of 0.75 μg/kg/min was confirmed for the cangrelor plus SOC andplacebo plus SOC groups.

In the placebo plus SOC group, patients received only SOC, in which thethienopyridine is discontinued after the need for surgery had beendetermined and a placebo infusion is administered. In the cangrelor plusstandard of care (SOC) group, a cangrelor infusion was started inaddition to SOC when the thienopyridine was discontinued after the needfor surgery had been determined. The infusions (cangrelor or matchingplacebo) were continued throughout the pre-operative period. Patientscan wait 5 days after discontinuation of clopidogrel before undergoingsurgery but the timing of surgery can vary and be left to the discretionof the health care practitioner with a maximum of 7 days of cangrelorinfusion.

Daily measurements of platelet inhibition were taken using theVerifyNow® P2Y₁₂ assay system.

All patients randomized receive SOC and waited up to five days afterdiscontinuation of thienopyridine before undergoing CABG. Anti-platelettherapy with aspirin was maintained during this time. Anti-thromboticssuch as unfractionated heparin and enoxaparin were allowed and given atthe discretion of the health care provider. It was recommended thatenoxaparin be discontinued >24 hours before CABG although concomitantuse of other anti-platelet and anti-thrombic agents is contemplated bythe invention described here. It was recognized that clinical events mayoccur leading to surgery before the 5 day waiting period is completedand therefore the decision to proceed to surgery was left to thediscretion of the health care provider.

For patients randomized to the cangrelor arm, cangrelor infusion wasstarted as quickly as possible and no more than 6 hours afterrandomization. Patients received an infusion of cangrelor, in additionto their SOC therapy, at a rate of 0.75 μg/kg/min.

Cangrelor was infused continuously via a dedicated peripheral or centralline for at least about 2 days and up to about 7 days. The dose ofcangrelor remained constant during the infusion period. The cangrelorinfusion was terminated at least one and no more than six hours beforeinduction of anesthesia for the scheduled CABG surgery. Induction ofanesthesia is defined as the start time of IV anesthesia. Patients wereinfused with cangrelor for a minimum of 48 hours prior to termination.

Patients not randomized to receive cangrelor received a placebo infusionadministered in the same manner as the cangrelor infusion in addition totheir SOC therapy.

FIG. 4A and FIG. 4B includes a table that summarizes the studyassessments by time point. This study consisted of 5 periods:Screening/Randomization Period, Pre-operative (Days 1-7 defined as theperiod from randomization to discontinuation of cangrelor),Intra-operative (from discontinuation of cangrelor to end of CABGsurgery), Post-operative Follow-up (from end of CABG surgery to hospitaldischarge), and 30-Day Follow-up (30+5 days from time of CABG).

Pre-operative Period (Randomization until discontinuation of cangrelor).Just prior to the administration of cangrelor, a VerifyNow® P2Y₁₂ Assaywas performed to obtain a baseline assessment. Testing was performedirrespective of the timing of last dose of thienopyridine received.Immediately following the VerifyNow® P2Y₁₂ Assay, the cangrelorcomposition was prepared and an infusion at the rate of 0.75 μg/kg/minwas started. This infusion was maintained until 1 to 6 hours prior toanesthesia administration for the CABG surgery. The following tests wereperformed daily, at approximately the same time, during all days ofcangrelor infusion: Hematology labs [hemoglobin, hematocrit, white bloodcells (WBC), and platelet count] PRU and percent platelet inhibitiondetermined by VerifyNow® P2Y₁₂ Assay Assessment of concomitantmedications. Within 12 hours prior to surgery, the following procedureswere conducted: Additional VerifyNow® P2Y₁₂ assay just prior tocangrelor termination. If the last on-infusion VerifyNow® sample waswithin 12 hours of cangrelor discontinuation, an additional draw was notrequired prior to termination of cangrelor.

Table 1 below represents the results of cangrelor and placebo treatmentduring the pre-operative period.

TABLE 1 Summary of PRU by Day Cangrelor Placebo Stat (N = 93) (N = 90)Screening Patients w/PRU <240 n/N (%) 53/85 (62.4) 45/86 (52.3) PRU: N85 86 MEAN ± SD 210.9 ± 94.0  214.1 ± 85.9 MEDIAN  201.0  233.5 (Q1, Q3)166, 280  151, 279 (MIN, MAX) 3, 418  10, 395 Day 1 sample Patientsw/PRU <240 n/N (%) 80/80 (100)  34/76 (44.7) PRU: N 80 76 MEAN ± SD 45.5± 47.1 232.7 ± 74.2 MEDIAN   31.0  249.0 (Q1, Q3) 5, 78  178, 287 (MIN,MAX) 0, 169  47, 367 Day 2 sample Patients w/PRU <240 n/N (%) 69/70(98.6) 25/73 (34.2) PRU: N 70 73 MEAN ± SD 58.8 ± 58.1 239.2 ± 71.1MEDIAN   40.0  256.0 (Q1, Q3) 6, 100 218, 282 (MIN, MAX) 0, 271  64, 354Day 3 sample Patients w/PRU <240 n/N (%) 55/55 (100)  21/57 (36.8) PRU:N 55 57 MEAN ± SD 59.2 ± 59.8 250.4 ± 64.7 MEDIAN   52.0  263.0 (Q1, Q3)8, 117 200, 306 (MIN, MAX) 0, 229 105, 358 Day 4 sample Patents w/PRU<240 n/N (%) 33/33 (100)   7/34 (20.6) PRU: N 33 34 MEAN ± SD 80.3 ±61.7 236.5 ± 65.5 MEDIAN   78.0  296.0 (Q1, Q3) 33, 115  241, 344 (MIN,MAX) 1, 219 118, 406 Day 5 sample Patients w/PRU <240 n/N (%)  7/7 (100) 6/24 (25.0) PRU: N  7 24 MEAN ± SD 52.1 ± 58.1 284.0 ± 64.0 MEDIAN  30.0  285.5 (Q1, Q3) 9, 117 244, 328 (MIN, MAX) 7, 151 140, 388 Day 6sample Patients w/PRU <240 n/N (%)  6/6 (100)  3/14 (21.4) PRU: N  6 14MEAN ± SD 62.7 ± 74.7 291.3 ± 54.1 MEDIAN   45.5  280.0 (Q1, Q3) 9, 67 250, 329 (MIN, MAX) 3, 206 217, 399 Day 7 sample Patients w/PRU <240 n/N(%)  1/1 (100)  0/2 (0.0) PRU: N  1  2 MEAN ± SD 3.0 ± .  343.5 ± 4.9MEDIAN   3.0  343.5 (Q1, Q3) 3, 3  340, 347 (MIN, MAX) 3, 3  340, 347Last on-treatment sample Patients w/PRU <240 n/N (%) 83/84 (98.8) 26/84(31.0) PRU: N 34 84 MEAN ± SD 68.9 ± 67.8 283.7 ± 68.3 MEDIAN   53.0 263.5 (Q1, Q3) 8, 110 227, 311 (MIN, MAX) 0, 271  81, 389 Lastpost-treatment pre-CABG Patients w/PRU <240 n/N (%) 21/78 (26.9) 15/75(20.0) PRU: N 78 75 MEAN ± SD 279.7 ± 106.5 297.8 ± 67.3 MEDIAN  293.0 299.0 (Q1, Q3) 228, 357  256, 345 (MIN, MAX) 1, 471 144, 445

The data in Table 1 indicates that infusion of Cangrelor at a dose of0.75 μg/kg/min between day 1 to day 7 maintains PRU values below 240 inover 90% of the patients studied. The table further indicates that forthe “last post-treatment pre-CABG” where cangrelor infusion isterminated but prior to CABG, the level of PRU has resumed to levelsprior to cangrelor treatment.

Intra-operative Period (Period from discontinuation of cangrelor untilend of CABG surgery) The Intra-operative period started at terminationof cangrelor infusion (surgery start is defined as time of firstincision). Cangrelor infusion was stopped at least 1 hour and a maximumof 6 hours prior to administration of anesthesia for surgery. Standardof care treatment was used for the surgical period. Collection of thefollowing assessments were conducted during this period: Serumcreatinine and LFTs—following discontinuation of cangrelor but prior tosurgery (surgery start time is defined as the time of first surgicalincision). VerifyNow® P2Y₁₂ assay just prior to first surgical incision.Concomitant medications and assessments of adverse events, seriousadverse events and clinical endpoints.

In the case of administering and ceasing the therapy prior to surgery inaccordance with one embodiment of the present invention, such use allowspatients to undergo surgery or other invasive procedures withoutexcessive perioperative bleeding.

Table 2 represents the bleeding risks associated with cangrelor andplaceblo treatment.

TABLE 2 Summary of CABG Related Bleeding during the CABG Procedurethrough Hospital Discharge Cangrelor Placebo Stat (N = 105) (N = 102)CABG related n/N (%) 10/102 (9.8)  10/96 (10.4) bleeding Fatal n/N (%) 00 bleeding Periop. n/N (%) 0 0 intracranial bleeding Re operation n/N(%) 2/102 (2.0) 2/96 (2.1) for bleeding Whole Blood n/N (%) 7/102 (6.9)8/96 (8.3) or pRBC Transfusion >=5 units 24 hour CT n/N (%) 3/102 (2.9)4/96 (4.2) output >=2 L

The results of Table 2 indicates that bleeding risk associated withcangrelor treatment is the same as or similar to treatment with placebo.

Table 3 represents the overall incidence of ischemic events

TABLE 3 Overall Incidence of Ishcemic Events Cangrelor Placebo SStat (N= 106) (N = 101) Pre-procedure Death/MI/IDR/Stroke n/N (%) 6/106 (5.7)4/101 (4.0) Death n/N (%) 1/106 (0.9) 3/101 (3.0) MI n/N (%) 2/106 (1.9)0/101 (0.0) IDR n/N (%) 4/106 (3.8) 0/101 (0.0) Stroke n/N (%) 0/106(0.0) 1/101 (1.0) Post-procedure Deat/MI/IDR/Stroke n/N (%) 4/102 (3.9) 4/96 (4.2) Death n/N (%) 1/102 (1.0)  2/96 (2.1) MI n/N (%) 2/102 (2.0) 1/96 (1.0) IDR n/N (%) 2/102 (2.0)  0/96 (0.0) Stroke n/N (%) 1/102(1.0)  1/96 (1.0) Pre and Post-procedures Death/MI/IDR/Stroke n/N (%)10/106 (9.4)  8/101 (7.9) Death n/N (%) 2/106 (1.9) 5/101 (5.0) MI n/N(%) 4/106 (3.8) 1/101 (1.0) IDR n/N (%) 6/106 (5.7) 0/101 (0.0) Stroken/N (%) 1/106 (0.9) 2/101 (2.0)

The results of Table 3 indicates that the ischemic events relating tothe methods described herein with the use of cangrelor is comparable tothe placebo.

Post-operative Period (Period from end of CABG surgery to hospitaldischarge) The following procedures were performed following surgery(end of CABG surgery is defined as the placement of the last suture):VerifyNow® P2Y₁₂ 2 Assay was performed within 1 hour following surgeryHematology labs, 12 lead-ECG and VerifyNow™ P2Y₁₂ Assay were performed24-hours (±1 h) following surgery. Chest tube output will be assessed at4 hours (±1 h) and 24 hours (±1 h) following surgery.

Example 3

In another example and in accordance with one embodiment of the presentinvention, the administration of the at least one reversible,short-acting P2Y₁₂ inhibitor occurs during an invasive procedure beingperformed on the subject. In this manner, it is contemplated that theadministration of the inhibitor would occur intravenously as the subjectcannot take the therapy orally.

Example 4a

In another example and in accordance with another embodiment of thepresent invention, the administration of the at least one reversible,short-acting P2Y₁₂ inhibitor occurs after an invasive procedure has beenperformed on the subject. The administration of the inhibitor in thepost surgery scenario can occur in a variety of methods as describedabove. It is contemplated that the administration of the inhibitor mayalso occur intravenously post surgery if the subject cannot take thetherapy orally, for example, if the subject is comatose.

Example 4b

The study for using cangrelor in early post-operative period

Current standard of care for anti-platelet maintenance therapy after PCIin patients with implanted stents is based on recommendations of theAmerican College of Cardiology/American Heart Association (ACC/AHA)guidelines (Fleisher L A, et al, ACC/AHA 2007 guidelines onperioperative cardiovascular evaluation and care for noncardiac surgery:a report of the ACC/AHA Task Force on Practice Guidelines. Circulation.2007 Oct. 23; 116(17):e418-99) that suggest an early initiation of dualanti-platelet therapy and continuation of maintenance therapy withaspirin and clopidogrel after PCI from 6 to 12 months, depending on thestent type, in order to prevent post-procedural stent thrombosis. Bothaspirin and clopidogrel are irreversible platelet antagonists, thereforeACC/AHA guidelines recommend cessation of clopidogrel beforenon-emergent surgical procedures in order to minimize bleeding risks.

However, should patients with implanted stents require a surgicalprocedure, early cessation of clopidogrel would increase the risk forischemic events and stent thrombosis due to a “rebound” effect ofplatelet activation (Berger et al., Circulation. 2002 Oct. 22;106(17):2284-7; Ho et al. JAMA. 2008 Feb. 6; 299(5):532-9). Conversely,maintaining irreversible platelet inhibition with aspirin andclopidogrel leads to unacceptable operative bleeding risk (Fox et al.,Circulation. 2004; 110; 1202-1208; Shim et al., J Thorac CardiovascSurg. 2007 July; 134(1):59-64; Pickard et al., Pharmacotherapy. 2008March; 28(3):376-92. Review).

Because of the risk of bleeding from the surgical sites, surgeons preferto avoid using anticoagulant agents in early post-operative periodespecially with irreversible oral therapy that will not allow predictingthe level of platelet inhibition and fast recovery of platelet functionwhen surgical procedure could be associated with high risk ofpost-operative bleeding.

It is well known that surgical interventions trigger platelet activationand aggregation, hence increasing the risk of stent thrombosis inpost-operative period if patient do not continue anti-platelet therapy.

It has been demonstrated in several studies that early initiation ofanticoagulant therapy may diminish the risk of venous thrombosis (SegersA. J Thromb Haemost. 2008 August; 6(8):1313-8; Turpie et al., Lancet.2009 May 1), however there is no consensus or standard antiplatelettherapy regimen designed to reduce the risk of arterial stent thrombosisin patients with implanted stents requiring surgical procedures.

Typically, at conclusion of surgical procedure a complete hemostasis isachieved, however, the risk of bleeding from the surgical site remainshigh during the first post-operative hours. Initiation of anti-platelettherapy during the immediate-early period after surgery may furtherincrease that risk. Conversely, a delay of continuation of anti-plateletmaintenance therapy will significantly increase the risk of stentthrombosis, considering that surgical procedure triggers plateletactivation and aggregation. Therefore, an early therapy with reversibleanti-platelet agent that could be titrated to a desirable level ofplatelet inhibition and have ultra-short platelet function recovery timecould be beneficial in preventing stent thrombosis in that category ofpatients. Moreover, this type of agent will be safe because it may allowcomplete recovery of platelet function after discontinuation in case ofbleeding.

Cangrelor is a potent, reversible and specific P2Y₁₂ receptor antagonistthat would allow overcoming the limitations of currently used dualanti-platelet therapy with aspirin and clopidogrel thanks to its rapidonset and offset of action with steady-state plasma concentrations thatcan be achieved within minutes and titrated to modulate the level ofplatelet inhibition and most importantly, it is rapidly metabolized withan short half-life, allowing complete recovery of platelet function inless than 60 min. Therefore, cangrelor could be an ideal anti-plateletagent for managing platelet inhibition in early post-operative period inpatients with implanted stents requiring a surgical procedure.

The optimal platelet inhibitory dose and regimen for cangrelor infusionin post-operative period and transitioning to oral anti-platelet therapycan be determined.

The patient population can be ACS patients with implanted stents afterPCI who require a major surgical procedure (CABG, GI anastomoses,pulmonary resection, prostatectomy, orthopedic procedures, etc.), N=40subjects (4 groups with 10 subjects in each group). Cangrelor infusionwill be initiated 1-2 hours after completion of surgical procedure atsurgeons' discretion. The subjects will be randomized into the followinggroups:

Group 1: Cangrelor 0.5 μg/kg/min dose infusion for 24 hrs transitioningto oral antiplatelet therapy with 300 mg of clopidogrel loading doseafter infusion discontinuation followed by 75 mg daily maintenance dosethereafter

Group 2: Cangrelor 0.5 μg/kg/min infusion for 24 hrs transitioning tooral antiplatelet therapy with 600 mg of clopidogrel loading dose afterinfusion discontinuation followed by 75 mg daily maintenance dosethereafter

Group 3: Cangrelor 1 μg/kg/min infusion for 24 hrs transitioning to oralantiplatelet therapy after infusion discontinuation transitioning tooral antiplatelet therapy with 300 mg of clopidogrel loading dose afterinfusion discontinuation followed by 75 mg daily maintenance dosethereafter

Group 4: Cangrelor 1 μg/kg/min infusion for 24 hrs transitioning to oralantiplatelet therapy after infusion discontinuation transitioning tooral antiplatelet therapy with 600 mg of clopidogrel loading dose afterinfusion discontinuation followed by 75 mg daily maintenance dosethereafter

The primary endpoints will be: (1) acute stent thrombosis during the 48hrs after the surgical procedure, and (2) major and minor bleedingsduring the 48 hrs after the surgical procedure.

The methods of evaluation will be: (1) platelet aggregation usingVerifyNow-P2Y₁₂ test, (2) hemodynamic measurements, (3) blood tests, (4)clinical observations for minor capillary bleeding signs (petechia,hematoma), (5) Diagnostic imaging of intracranial, peritoneal andpleural cavities using CT, MRI, US, when necessary to detect potentialbleeding complications (blood accumulation).

Those of ordinary skill in the art will recognize that manymodifications and variations of the present invention may be implementedwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modification andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

The invention claimed is:
 1. A method of inhibiting platelet activity ina subject comprising: treating the subject with a therapeuticallyeffective amount of a thienopyridine; ceasing administration of thethienopyridine; and administering to the subject an amount of cangrelorselected to cause the measured P2Y₁₂ reaction unit (PRU) to bemaintained at or below about 240 during administration of cangrelor;wherein the rate of administration of cangrelor is at the range ofbetween about 0.1 μg/kg/min to about 5 μg/kg/min.
 2. The method of claim1 wherein the thienopyridine is clopidogrel.
 3. The method of claim 1wherein the thienopyridine is selected from the group consisting ofclopidogrel, ticlopidine, and prasugrel.
 4. The method of claim 1wherein the rate of administration of cangrelor is about 0.75m/kg/min.5. The method of claim 1 wherein the measured PRU is maintained at arange of about 30 to about 240 during administration of cangrelor. 6.The method of claim 1 wherein the administration of cangrelor commenceswithin 3 days of the ceasing administration of the thienopyridine. 7.The method of claim 1 wherein cangrelor is continuously administeredbetween about 2 days to about 7 days.
 8. The method of claim 1 furthercomprising wherein administration of cangrelor is discontinued; andallowing platelet activity to return to pre-cangrelor administrationlevels wherein the measured PRU level is greater than 240, prior to thepatient undergoing an invasive procedure.
 9. The method of claim 1wherein cangrelor is concurrently administered with a second therapeuticagent.
 10. The method of claim 9 wherein said second therapeutic agentis streptokinase, alteplase, reteplase, urokinase, tenecteplase,aspirin, bivalirudin, heparin warfarin, eptifibatide, abciximab ortirofiban.